package org.apache.lucene.index;

/**
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

/**
 * Extends <code>TermFreqVector</code> to provide additional information about
 * positions in which each of the terms is found. A TermPositionVector not
 * necessarily contains both positions and offsets, but at least one of these
 * arrays exists.
 */
public interface TermPositionVector extends TermFreqVector {

	/**
	 * Returns an array of positions in which the term is found. Terms are
	 * identified by the index at which its number appears in the term String
	 * array obtained from the <code>indexOf</code> method. May return null if
	 * positions have not been stored.
	 */
	public int[] getTermPositions(int index);

	/**
	 * Returns an array of TermVectorOffsetInfo in which the term is found. May
	 * return null if offsets have not been stored.
	 * 
	 * @see org.apache.lucene.analysis.Token
	 * 
	 * @param index
	 *            The position in the array to get the offsets from
	 * @return An array of TermVectorOffsetInfo objects or the empty list
	 */
	public TermVectorOffsetInfo[] getOffsets(int index);
}